Drainage catheters are widely used when patients are unable to reliably void themselves, typically after surgery that is related to a urinary function. For men, the use of a drainage catheter may be related to surgery for a diseased prostrate gland. For women, a drainage catheter may be needed after surgery to repair the pelvic floor or to support the urethra. For patients of either sex, a urinary catheter may be needed when the patient is immobilized in a hospital bed. These catheters often take the form of what is known as a Foley catheter, which includes a drainage lumen from the bladder to outside the body.
A Foley catheter also includes a balloon placed in the urinary bladder for retention of the catheter. The balloon is inflated by using pressurized water or saline solution. The water or saline is added through an inflation lumen that is independent and separate from the drainage lumen. The inflation lumen extends from the balloon inside the bladder to a fitting outside the body. The fitting is used to inflate the balloon, which then holds the catheter reliably within the patient's urinary bladder.
In order to place the Foley catheter and the uninflated balloon into the patient's body, an access sheath is frequently used. An access sheath, such as one similar to those depicted in U.S. Pat. Nos. 5,380,304 and 5,700,253, assigned to the assignee of the present invention, is placed within the urethra. The catheter is then placed into the patient through the access sheath. The access sheath typically uses a very lubricious hydrophilic coating on its outside to ease the passage of the access sheath through the urethra.
One difficulty in using access sheaths is that once the Foley catheter has been placed, it may be difficult to remove the access sheath, because the proximal (outside) end of the Foley, with its fittings may be too wide to allow removal of the access sheath. Accordingly, access sheaths, such as those described in WIPO Publication No. WO 93/04726, have now been designed as “tear-away” sheaths, that is, they are easy to split along their entire length. Thus, the access sheath may be torn down its length and removed from the patient at will.
A problem with this approach is that, even with hydrophilic coatings, the process of tearing and removal of the access sheath is traumatic to the patient. What is needed is a Foley catheter that allows removal of the access sheath with a minimum of trauma to the patient. What is needed is a Foley catheter that can be implanted with the aid of an access sheath, and which allows removal of the access sheath once the Foley catheter is implanted.